To resume fastly you have to reach every conclusions in the game, you don't have to launch each conclusions, you just have to find them in your deductions, and click on them (when you have the choice to condemn or absolve the criminals, the game will save. It worked for me)

Chaper 5 The Kew Gardens Drama : 6 Conclusions - Deadly Syndicate are the Killers( Theft and murder + Set stole everything) - Albert Dunne is the Killer(Sect is not involved + Albert's motive + Albert's studies) - Miss Margaret White is the murderer(Sect is not involved + Disagreement + White's situation + White's knowledgeYOU HAVE TO DO THOSE BEFORE YOU FIND THE NEXT AFTER THAT IT WON'T BE POSSIBLE ANYMORE - Martyn Hamisch is the Killer (Sect is not involved + Martyn's motive + Martin Hamish's opportunity + Mr. Dunne was poisoned) - There is no Accomplice (Albert is not involved + White is not involved + Hamish is guilty) - Albert is the Accomplice(Martyn's timeline + Albert's timeline) -Miss White is the Accomplice(Martyn's timeline + White's timeline)